The present invention relates to a process for monitoring signals provided as outputs from a transmitting device. The signals include two sinusoidal, offset-free signals of the same amplitude. Ideally, it is preferred that the two signals have a phase difference of 90.degree..
Such processes are disclosed, for example, by the German Published Patent Application 38 43 108 and have been successfully carried out in the past. However, the expenditure for circuit engineering using such processes is considerable.
The present invention provides a process of the type mentioned at the outset. This process detects disturbances in the pattern (or waveform) of the output signals using a few simple process steps.